ANIMAL

In vitro fertilization using sex-sorted boar sperm mediated by magnetic nanoparticles

Hakjae Chung1   Sunyoung Baek1   Soojin Sa1   Youngshin Kim1   Joonki Hong1   Eunseok Cho1   Jihwan Lee2   Seungmin Ha2   Jungho Son3   Seunghwan Lee4   Inchul Choi4,*   Kyungwoon Kim5,*   

1Swine Science Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Korea
2Dairy Science Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Korea
3Chungnam Techno Park, Cheonan 31035, Korea
4Division of Animal and Dairy Sciences, College of Agriculture and Life Sciences, Chungnam University, Daejeon 34134, Korea
5Planning and Coordination Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Korea

Abstract

A wide range of techniques have been developed to separate X or Y- chromosome-bearing sperm. In particular, bovine semen sex-sorted by using flow cytometry based on differences in the amount of DNA between X and Y chromosome bearing sperm is used in dairy farms. The first piglets were produced using sex-sorted sperm 30 years ago. However, sexed sperm have not been commercially available in pigs because the flow cytometry technique is not capable of sorting the high number of sperm required for porcine artificial insemination (AI), and the prolonged exposure to an electrical filed might damage to the DNA in sperm. The purpose of this study was to evaluate a boar sperm sorting method based on magnetic nanoparticles. A flow cytometer assay verified the efficacy of the magnetic nanoparticles (> 90% of sex-sorted sperm). In addition, a duplex polymerase chain reaction (PCR) assay using sex chromosome specific genes including SRY (sex-determining region Y; male), ZFY (zinc finger protein Y-linked; male), and ZFX (zinc finger protein X-linked; female) showed that in vitro fertilized porcine embryos by X and Y-chromosome bearing sperm were 100% female (40/40) and 72% female (35/48), respectively, at 8-cell or morula stages, suggesting that the sex-sorted sperm were fertile. In conclusion, our findings suggest that the sex-sorted method based on magnetic nanoparticles can be utilized for porcine sex-sorted AI.

Figures & Tables

Fig. 1. Efficiency of sex-sorting by magnetic nanoparticles. The images show population of both X and Y chromosome bearing sperm, X-chromosome bearing sperm, and Y-chromosome bearing sperm. The accuracy of sorting was analyzed by the flow cytometer. DAPI, 4′,6-diamidino-2-phenylindole; Cy3, cyanine 3.